In a motor vehicle, a “pulling” state, for example, can occur such that a driver of the vehicle has to input torque into a steering system thereof to maintain a straight path. This state can be caused by vehicle, road, and/or weather conditions (such as a crosswind that requires a force for the steering system to overcome) or an imbalance in the steering system (such as if a valve is balanced in a “null” position and a torsion bar is on center, but a valve spool is creating pressure in the steering system). Either way, an input torque correction is required by the driver.
In the steering system, a recirculating ball steering gear may use an open-center-rotary valve to port hydraulic fluid to either side of a piston of the gear upon inputs from the driver. However, some systems may not have any capability to perform additional “performance” features or functions such as park-assist, lane-keeping, lead-and-pull compensation, driver-alert, active return-to-center, active dampening, or stability-control assist.
Also, an electric power-steering system or hydraulic rack-and-pinion steering system may not have sufficient output to perform a park-assist or may not be able to be packaged in the vehicle. A magnetic actuator may be used to apply torque to a hydraulic valve of a steering system independently of input from the driver. Such use allows the steering system to perform, for example, lead-and-pull compensation, active return-to-center, and active dampening.
However, to perform park-assist, size of the magnetic actuator may need to be increased such that a sufficient amount of torque is produced in the steering system to generate full hydraulic assist. Therefore, the magnetic actuator may be difficult to package in the vehicle.
Accordingly, it is desirable to provide a steering system of a vehicle that has the capability to perform the additional “performance” features. More specifically, it is desirable to provide a hydraulically assisted power-steering system that has sufficient output and can be packaged in the vehicle.